蒌蒿(Artemisia selengensis)根际耐镉产酸细菌的筛选鉴定及其生物学特性

根际细菌的筛选研究有助于构建有效的植物-微生物联合修复体系.采用稀释平板法从蒌蒿根际土壤中分离耐Cd产酸的根际细菌,并对菌株Pb2+、Cu2+和Sb3+的耐受性,分泌吲哚乙酸(IAA)、铁载体、解磷特性及对土壤中Cd的活化效果进行了测定,基于形态特性、生理生化测定和16S rDNA 序列分析对目标菌株进行了分类鉴定.结果表明,从蒌蒿根际土壤中分离到能耐50 mg/L镉浓度且产酸能力较强的根际细菌1株T3,菌株T3对Pb2+、Cu2+和Sb3+均具一定的耐受性,能分泌一定量的IAA和铁载体,但不具解磷特性,能明显增加土壤中有效态镉的含量,经鉴定可初步确定为芽孢杆菌属(Bacillus sp.).为进一步研究其在蒌蒿修复镉污染土壤中的作用奠定了基础.

Screening,identification and biological characterization of cadmium-resistant producing acid rhizospheric bacteria from Artemisia selengensis

Screening and studying on rhizospheric bacteria laid a theoretical basis for building effective combined remediation system of plant and microorganism.Cadmium-resistant producing acid rhizospheric bacteria was isolated from rhizospheric soil of Artemisia selengensis by dilution-plate method.The tolerance of Pb2+,Cu2+,Sb3+, the features of IAA-producing,siderophores,phosphate solubilization as well as the activation effect of cadmium in soil of strain were determinated.Strain was identified based on morphological,physiological-biochemical properties and 16S rDNA sequence analysis.The results showed that one cadmium-resistant concentration up to 50 mg/L and strong ability to secrete acid rhizospheric bacteria named as T3 was isolated from rhizospheric soil of Artemisia selengensis. Strain T3 had certain tolerance to Pb2+,Cu2+,Sb3+,could produce a certain amount of IAA and siderophores,but not possess phosphate-solubilizing ability, could increase significantly content of available cadmium in the soil.T3 was identified primarily as Bacillus sp.This research lays the foundation for further study on its role in remediation cadmium contaminated soil of Artemisia selengensis.